Oral compositions

ABSTRACT

Disclosed are oral compositions containing particular pyrophosphate salts which provide an anticalculus benefit.

This is a continuation of application Ser. No. 591,228, filed on Mar.19, 1984, now U.S. Pat. No. 4,515,772, May 7, 1985, which is acontinuation of application Ser. No. 391,040, Jun. 22, 1982, nowabandoned.

TECHNICAL FIELD

The present invention relates to oral compositions, liquid dentifrices,toothpastes and mouthwashes, which provide an anticalculus benefit.

BACKGROUND OF THE INVENTION

Dental calculus, or tartar as it is sometimes called, is a deposit whichforms on the surfaces of the teeth at the gingival margin. Supragingivalcalculus appears principally in the areas near the orifices of thesalivary ducts; e.g., on the lingual surfaces of the lower anteriorteeth and on the buccal surfaces of the upper first and second molars,and on the distal surfaces of the posterior molars.

Mature calculus consists of an inorganic portion which is largelycalcium phosphate arranged in a hydroxy-apatite crystal latticestructure similar to bone, enamel and dentine. An organic portion isalso present and consists of desquamated epithelial cells, leukocytes,salivary sediment, food debris and various types of microorganisms.

As the mature calculus develops, it becomes visibly white or yellowishin color unless stained or discolored by some extraneous agent. Inaddition to being unsightly and undesirable from an aestheticstandpoint, the mature calculus deposits are constant sources ofirritation of the gingiva.

A wide variety of chemical and biological agents have been suggested inthe art to retard calculus formation or to remove calculus after it isformed. Mechanical removal of this material periodically by the dentistis, of course, routine dental office procedure.

The chemical approach to calculus inhibition generally involveschelation of calcium ion and/or crystal growth inhibition which preventsthe calculus from forming and/or breaks down mature calculus by removingcalcium.

The prior art discloses a number of chelating agents for this purpose.British Pat. No. 490,384, Feb. 15, 1937, discloses oral compositionscontaining ethylenediaminetetraacetic acid, nitrilotriacetic acid andrelated compounds as anticalculus agents. U.S. Pat. No. 3,678,154, Jul.18, 1972 to Widder et al discloses oral compositions containing certainpolyphosphonates and fluoride. U.S. Pat. No. 3,737,533, Jun. 5, 1973 toFrancis discloses oral compositions containing certain carbonyldiphosphonates.

In addition to the above references, the prior art discloses dentifricesand mouthwashes containing soluble pyrophosphate salts which have beenindicated for a variety of purposes. Included among such references areU.S. Pat. No. 2,941,926, Jun. 21, 1960 to Salzmann et al which disclosesdental powders containing chlorophyll and pyrophosphate salts. U.S. Pat.No. 3,137,632, Jun. 16, 1964 to Schiraldi discloses toothpastescontaining pyrophosphate salts. U.S. Pat. Nos. 3,927,201 and 202, Dec.16, 1975 to Baines et al and Harvey et al, respectively, disclosestoothpastes which utilize soluble pyrophosphates as abrasives. U.S. Pat.Nos. 4,244,931, Jan. 13, 1981 and 4,247,526, Jan. 27, 1981 to Jarvis etal disclose pyrophosphate salts in dicalcium phosphate systems. Jap.Patent Application Disclosure No. 4945-1974 discloses solublepyrophosphates in a variety of dentifrice systems. U.S. Pat. No.4,333,551, Apr. 6, 1982 to Parran discloses tetraalkali metal salts inmouthwash compositions. Finally Draus, Lesniewski and Miklos,Pyrophosphate and Hexametaphosphate Effects In Vitro Calculus Formation,Arch. Oral Biol., Vol. 15, pp. 893-896, (1970) disclose the in vitroeffectiveness of soluble pyrophosphate salts against calculus. However,they indicate that pyrophosphate would be inhibitied by pyrophosphatasein vivo.

In spite of the many disclosures in the anticalculus and pyrophosphateareas, the need for an effective anticalculus product still exists.Surprisingly mixtures of certain pyrophosphate salts can provide a safeand effective product while also not presenting difficult formulationproblems.

It is an object of the present invention to provide compositions whichdeliver an effective anticalculus benefit.

It is a further object of the present invention to provide an effectiveanticalculus product utilizing a mixture of soluble pyrophosphate salts.

It is still a further object of the present invention to provide aneffective method for treating calculus.

These and other objects will become more clear from the detaileddescription which follows.

All percentages and ratios used herein are by weight unless otherwisespecified.

SUMMARY OF THE INVENTION

The present invention embraces an oral composition in the form of amouthwash, liquid dentifrice or toothpaste comprising:

(a) from about 0% to about 70% of a dental abrasive selected from thegroup consisting silica, alumina, calcium pyrophosphate, insolublemetaphosphates and thermosetting polymerized resins;

(b) an amount of a fluoride source sufficient to supply from about 50ppmto 3500ppm of fluoride ions;

(c) an amount of a soluble pyrophosphate salt selected from the groupconsisting of dialkali metal and mixtures of dialkali metal andtetra-alkali metal pyrophosphate salts sufficient to provide at leastabout 1.5% P₂ O₇ ⁻⁴ ; and

(d) from about 2% to about 95% water

wherein the pH of said composition is from about 6.0 to about 10.0 andthe composition does not contain more than about 4.0 K₄ P₂ O₇.

The present invention also encompasses a method for retarding thedevelopment of dental calculus.

DETAILED DESCRIPTION OF THE INVENTION

The essential as well as optional components of the compositions of thepresent invention are described in the following paragraphs:

Dental Abrasive

The abrasives useful in the dentifrice composition aspect of the presentinvention include many different materials. Calcium pyrophosphate,including the β-phase calcium pyrophosphate prepared in accordance withthe teaching of Schweizer, U.S. Pat. No. 3,112,247, Nov. 26, 1963, canbe used. The β-phase calcium pyrophosphate is prepared by heatingγ-phase calcium pyrophosphate to 700-900° C. to change at least 50% ofthe γ-phase to β-phase and then immediately cooling. Another class ofabrasives for use herein are the particulate thermosetting polymerizedresins as described by Cooley et al in U.S. Pat. No. 3,070,510, Dec. 25,1962. Suitable resins include, for example, melamines, phenolics, ureas,melamine-ureas, melamineformaldehydes, urea-formaldehydes,melamine-urea-formaldehydes, cross-linked epoxides, and cross-linkedpolyesters.

Silica dental abrasives are also useful in the present compositions. Thesilica abrasive polishing material generally has an average particlesize ranging between about 0.1 to 30 microns, preferably 5 and 15microns. The abrasive can be precipitated silica or silica gels such asthe silica xerogels described in Pader et al; U.S. Pat. No. 3,538,230;issued Mar. 2, 1970 and incorporated herein by reference. Preferred arethe silica xerogels marketed under the tradename "Syloid" by the W. R.Grace & Company, Davison Chemical Division. Also preferred are theprecipitated silica materials such as those marketed by the J. M. HuberCorporation under the tradename, "Zeodent". The types of silica dentalabrasives useful in the toothpastes of the present invention aredescribed in more detail in DiGiulio, U.S. Pat. No. 3,862,307; issuedJan. 21, 1975, incorporated herein by reference.

Other suitable abrasives include alumina, and the insolublemetaphosphates such as insoluble sodium metaphosphate (IMP). Mixtures ofabrasives can also be used. In any case, the total amount of abrasive inthe dentifrice embodiments of this invention can range from 0% to 70% byweight of the dentifrice. Preferably, toothpastes contain from 10% to50% by weight of abrasive.

The preferred abrasives are the β-phase calcium pyrophosphate of U.S.Pat. No. 3,112,247; alumina insoluble metaphosphate; the resinousabrasives of U.S. Pat. No. 3,070,510; and the silica abrasives sincethey are more compatible with the agents. Most preferred are the silicaabrasives.

Fluoride Ion Source

The second essential component of the compositions herein is a fluorideion source, The number of such sources is great and includes thosedisclosed in U.S. Pat. No. 3,535,421, Oct. 20, 1970 to Briner et al,incorporated herein by reference. Typical materials include:

Stannous fluoride, potassium fluoride, lithium fluoride, cesiumfluoride, ammonium fluoride, aluminum fluoride, cupric fluoride, indiumfluoride, stannous fluorozirconate, lead fluoride, ferric fluoride,nickel fluoride, paladium fluoride, silver fluoride, zinc fluoride,zirconium fluoride, hexylamine hydrofluoride, laurylamine hydrofluoride,myristylamine hydrofluoride, decanolamine hydrofluoride,octadecenylamine hydrofluoride, myristoxyamine, hydrofluoride,diethylaminoethyloctoylamide hydrofluoride,diethanolamineoethyloleylamide hydrofluoride,diethanolaminopropyl-N'-octadecenylamine dihydrofluoride,1-ethanol-2-hexadecylimidazoline dihydrofluoride, octoylethanolaminehydrofluoride, octyltrimethylammonium fluoride,dodecylethyldimethylammonium fluoride, tetraethylammonium fluoride,dilauryldimethylammonium fluoride. Δ⁸,9-octadecenylbenzyldimethylammonium fluoride, dioctyldiethylammoniumfluoride, cyclohexylcetyldimethylammonium fluoride,furfuryllauryldimethylammonium fluoride,phenoxyethylcetyldimethylammonium fluoride,N:N'-tetramethyl-N:N;-dilaurylethylenediammonium difluoride,N-cetylpyridinium fluoride, N:N-dilauryl-morpholinium fluoride,N-myristyl-N-ethylmorpholinium fluoride,N-(octylaminocarbonylethyl)-N-benzyl-dimethylammonium fluoride,N(β-hydroxydodecyl) trimethylammonium fluoride,N-phenyl-N-hexadecyldiethylammonium fluoride,N-cyclohexyl-N-octadecyldimethylammonium fluoride,N-(2-carbomethoxyethyl)-N-benzyldimethylammonium fluoride,N-(2-carbocyclohexoxyethyl)-N-myristyldimethylammonium fluoride,N-(2-carbobenzyloxyethyl)-N-dodecyldimethylammonium fluoride,N-[2-(N:N'-dimethylaminocarbonyl)-ethyl]-N-dodecyldiethylammoniumfluoride, N-carboxymethyl-N-cicosyldimethylammonium fluoride, betainehydrofluoride, sarcosine stannous fluoride, alanine stannous fluoride,glycine potassium fluoride, sarcosine potassium fluoride, glycinehydrofluoride, lysine hydrofluoride, alanine hydrofluoride, betainezirconium fluoride, sodium monofluoro phosphate and mixtures thereof.Sodium fluoride is the preferred fluoride source.

The amount of the fluoride ion source should be sufficient to providefrom about 50 ppm to 3500 ppm, preferably from about 500 ppm to 3000 ppmof fluoride ions.

Di alkali Metal and Tetra alkali Metal Salts

The pyrophosphate salts useful in the present compositions includedialkali metal pyrophosphate and mixtures of the dialkali metal andtetraalkali metal pyrophosphate salts. Na₂ H₂ P₂ O₇, Na₄ P₂ O₇ and K₄ P₂O₇ in their unhydrated as well as hydrated forms are the preferredspecies. The levels of each of these species which preferably are usedin the compositions are as follows (all are in the unhydrated form).

Na₂ H₂ P₂ O₇ --0.5%--13.8%

Na₄ P₂ O₇ --0--6.0%

K₄ P₂ O₇ --0--4.0%

The minimum amount of P₂ O₇ ⁻⁴ required in the present compositions,1.5% can therefore be provided solely by Na₂ H₂ P₂ O₇ or mixtures of Na₂H₂ P₂ O₇ with either or both of the tetra alkali metal salts. Preferredare binary mixtures of the sodium salts and ternary mixtures of thosewith the tetra potassium salt. The upper limits on the sodium speciesare determined by solubility considerations while the tetra potassiumlevel is established for taste reasons.

The pyrophosphate salts are described in more detail in Kirk & Othmer,Encyclopedia of Chemical Technology, Second Edition, Volume 15,Interscience Publishers (1968) incorporated herein by reference.

Water

Water is another essential component of the compositions of thisinvention. Water employed in the preparation of commercially suitableoral compositions should preferably be of low ion content and free oforganic impurities. Water comprises from about 2%. to about 95%,preferably from. about 20% to about 95% of the compositions of thisinvention. When in the form of toothpastes, the amount of water ispreferably from about 2% to about 45%, while mouthwashes preferablycontain from about 45% to about 95%.

Optional Components

In addition to the above described essential components, the oralcompositions of this invention can contain a variety of optionalconventional oral composition components. Such optional ingredientsinclude sudsing agents, flavoring agents, sweetening agents, antiplaqueagents, coloring agents, and pigments.

A preferred optional ingredient is a sudsing agent. Suitable sudsingagents are those which are reasonably stable and form suds throughout awide pH range, i.e., non-soap anionic, nonionic, cationic, zwitterionicand amphoteric organic synthetic detergents. Sudsing agents of thesetypes are described more fully in Agricola et al; U.S. Pat. No.3,959,458; issued May 25, 1976 and in Haefele; U.S. Pat. No. 3,937,807;issued Feb. 10, 1976. Both of these patents are incorporated herein byreference.

Anionic sudsing agents useful herein include the water-soluble salts ofalkyl sulfates having from 10 to 18 carbon atoms in the alkyl radicaland the water-soluble salts of sulfonated monoglycerides of fatty acidshaving from 10 to 18 carbon atoms. Sodium lauryl sulfate and sodiumcoconut monoglyceride sulfonates are examples of anionic surfactants ofthis type. Mixtures of anionic surfactants can also be employed.

The nonionic sudsing agents which can be used in the compositions of thepresent invention can be broadly defined as compounds produced by thecondensation of alkylene oxide groups (hydrophilic in nature) with anorganic hydrophobic compound which may be aliphatic or alkylaromatic innature. Examples of suitable nonionic sudsing agents include thePluronics, polyethylene oxide condensates of alkyl phenols, productsderived from the condensation of ethylene oxide with the reactionproduct of propylene oxide and ethylene diamine, ethylene oxidecondensates of aliphatic alcohols, long chain tertiary amine oxides,long chain tertiary phosphine oxides, long chain dialkyl sulfoxides andmixtures of such materials.

The zwitterionic synthetic sudsing agents useful in the compositions ofthe present invention can be broadly described as derivatives ofaliphatic quaternary ammonium, phosphonium, and sulfonium compounds, inwhich the aliphatic radicals can be straight chain or branched, andwherein one of the aliphatic substituents contains from about 8 to 18carbon atoms and one contains an anionic water-solubilizing group, e.g.,carboxy, sulfonate, sulfate, phosphate, orphosphonate.

The cationic sudsing agents useful in the compositions of the presentinvention can be broadly defined as quaternary ammonium compounds havingone long alkyl chain containing from about 8 to about 18 carbon atomssuch as lauryl trimethylammonium chloride; cetyl pyridinium chloride,cetyl trimethylammonium bromide;di-isobutylphenoxyethoxyethyl-dimethylbenzylammonium chloride;coconutalkyltrimethylammonium nitrite; cetyl pyridinium fluoride; etc.

The amphoteric sudsing agents useful in the present invention can bebroadly described as derivatives of aliphatic secondary and tertiaryamines in which the aliphatic radical can be straight chain or branchedand wherein one of the aliphatic substituents contains from about 8 toabout 18 carbon atoms and one contains an anionic water-solubilizinggroup, e.g., carboxylate, sulfonate, sulfate, phosphate, or phosphonate.

The sudsing agent can be present in the compositions of this inventionin an amount from about 0% to about 10% by weight of the totalcomposition.

Flavoring agents can also be added to the instant compositions. Suitableflavoring agents include oil of wintergreen, oil of peppermint, oil ofspearmint, oil of sassafras, and oil of clove. Sweetening agents whichcan be used include saccharin, dextrose, levulose, aspartame,D-tryptophan, dihydrochalcones,acesulfame and sodium cyclamate.Flavoring agents are generally used in the compositions at levels offrom about 0.4% to about 2% by weight and sweetening agents at levels offrom about 0.1% to about 5% by weight.

Binders can also be used with the toothpastes of of the presentinventions. Such binders include, for example, xanthan gum, carrageenan(Irish moss, Viscarin®), and carboxyvinyl polymers. These binders aregenerally present at a level of from about 0.1% to 1%.

Bis-biguanide antiplaque agents can also optionally be added to thecompositions of this invention. Such agents include chlorhexidine(1,6-bis [N⁵ -p-chlorophenyl-N¹ -biguanido]hexane), the soluble andinsoluble salts thereof and related materials such as 1,2-bis(N⁵-p-trifluoromethylphenyl-N¹ -biguanido)ethane are described more fullyin Haefele, U.S. Pat. No. 3,923,002, issued Jan. 20, 1976; Haefele, U.S.Pat. No. 3,937,807, issued Feb. 10, 1976; Procter & Gamble, Belgian Pat.No. 843,244, published Dec. 22, 1976 and Procter & Gamble, Belgian Pat.No. 844,764, published Jan. 31, 1977. These patents are incorporatedherein by reference.

If present, the optional antiplaque agents generally comprise from about0% to about 5% by weight of the compositions herein.

Another optional component of the compositions herein is a humectant.The humectant serves to keep the toothpaste compositions from hardeningupon exposure to air and in mouthwashes give a moist feel to the mouth.Certain humectants can also impart desirable sweetness of flavor tomouthwash and toothpaste compositions. The humectant, on a purehumectant basis, generally comprises from about 0% to 70%, preferablyfrom about 0% to 55%, by weight of the compositions herein.

Suitable humectants for use in this invention include edible polyhydricalcohols such as glycerine, sorbitol, xylitol and propylene glycol.Sorbitol is frequently employed as a 70% aqueous solution known asSorbo®.

The mouthwashes herein may also contain ethanol in an amount of fromabout 0 to about 30%

The pH of the compositions herein is in the range of 6.0 to 10.0,preferably from 7.3 to 9.0. The pH is preferably achieved through aproper balancing of the pyrophosphate salts or by the addition of analkaline or acidic agent.

Method of Manufacture

The compositions herein are made using conventional mixing techniques. Atypical method is described in Example I.

Industrial Applicability

The compositions of the present invention are used in a conventionalmanner.

The following examples further describe and demonstrate preferredembodiments within the scope of the present invention. The examples aregiven solely for the purpose of illustration and are not to be construedas limitations of this invention. Many variations thereof are possiblewithout departing from the invention's spirit and scope.

EXAMPLE I

The following is a toothpaste representative of the present invention.

    ______________________________________                                        Component             %                                                       ______________________________________                                        Distilled Water       16.484                                                  Sorbitol (70% Aqueous 49.563                                                  Solution)                                                                     Sodium Saccharin      0.300                                                   Dye Solution          0.350                                                   Precipitated Silica   20.00                                                   Sodium Fluoride       0.243                                                   Flavor                1.330                                                   Sodium Alkyl Sulfate (27.9%                                                                         5.000                                                   Aqueous Solution)                                                             Carbopol 940s*        0.180                                                   Xanthan Gum           0.600                                                   Na.sub.4 P.sub.2 O.sub.7                                                                            2.400                                                   Na.sub.2 H.sub.2 P.sub.2 O.sub.7                                                                    1.190                                                   K.sub.4 P.sub.2 O.sub.7 (63.5% Aqueous Solution)                                                    2.360                                                                         100.000%                                                ______________________________________                                         *A carboxy vinyl polymer offered by B. F. Goodrich Company.              

The above composition was made by combining the water and part of thesorbitol in an agitated mixture and heating this mixture to 140° F. TheNa₂ H₂ P₂ O₇, Na₄ P₂ O₇, saccharin, sodium fluoride and precipitatedsilica were then added in order and the total mixture was mixed for from5 to 10 minutes. The flavor, dye and surfactant were then added. In aseparate vessel the remainder of the sorbitol, the Carbopol and thexanthan gum were slurried together and then added to the main mix tank.The complete batch was mixed for about one-half hour and subsequentlymilled and deaerated.

EXAMPLE II

The following is another representative toothpaste of the presentinvention.

    ______________________________________                                        Component              %                                                      ______________________________________                                        Sorbitol (70% Aqueous Solution)                                                                      50.743                                                 Distilled Water        16.484                                                 Sodium Saccharin       0.300                                                  Dye Solution           0.350                                                  Precipitated Silica    20.000                                                 Sodium Fluoride        0.243                                                  Flavor                 1.330                                                  Sodium Alkyl Sulfate (27.9% Aqueous                                                                  5.000                                                  Solution)                                                                     Carbopol 940S          0.180                                                  Xanthan Gum            0.600                                                  Na.sub.4 P.sub.2 O.sub.7                                                                             3.400                                                  Na.sub.2 H.sub.2 P.sub.2 O.sub.7                                                                     1.370                                                                         100.000%                                               ______________________________________                                    

Both the composition of Example I and that of Example II are effectivein reducing calculus and possess acceptable cosmetic properties.

In addition to the levels and combinations of ingredients shown in theseexamples, others can be used which are consistent with the inventiondisclosed and claimed herein.

What is claimed is:
 1. A toothpaste composition comprising:(a) fromabout 10% to about 70% of which will allow for the pyrophosphate ionconcentration specified below; (b) an amount of a fluoride ion sourcesufficient to supply from about 50 ppm to about 3500 ppm of fluorideions; (c) an amount of a pyrophosphate salt selected from the groupconsisting of dialkali metal and mixtures of dialkali metal andtetraalkali metal pyrophosphate salts sufficient to provide at least1.5% P₂ O₇ ⁻⁴ ; and (d) the remainder water; wherein the pH of saidcomposition is from about 6.0% to about 10.0 and the composition doesnot contain more than about 4.0% K₄ P₂ O₇.
 2. A toothpaste compositionaccording to claim 1 wherein sodium fluoride is the fluoride ion source.3. An oral composition according to claim 1 wherein the pyrophosphateion is provided by a mixture of disodium pyrophosphate and tetrasodiumpyrophosphate.
 4. A toothpaste composition according to claim 1 whereinthe pyrophosphate ion is provided by a mixture of disodiumpyrophosphate, tetrasodium pyrophosphate and tetrapotassiumpyrophosphate.
 5. A toothpaste composition according to claim 1 which inaddition contains from about 0 to about 10% of a sudsing agent.
 6. Atoothpaste composition according to claim 1 which in addition containsfrom about 0.1% to about 1.0% of a binder.
 7. A toothpaste compositionaccording to claim 1 which in addition contains from about 0 to about70% of a humectant.
 8. A toothpaste composition in accordance with claim1 wherein the dental abrasive is β-phase calcium pyrophosphate.